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ETI to launch project to develop Flettner rotor sails for ships; seeking at least 10% improvement in fuel efficiency

The Energy Technologies Institute (ETI) in the UK is seeking partners for a new project which it hopes will deliver fuel savings of at least 10% for large shipping vessels.

The Flettner Rotor Supply, Install and Commission Project will deliver a full scale demonstrator of Flettner Rotor technology on a large ocean going vessel which the ETI intends to source for the demonstration phase. Flettner rotors use a spinning cylinder to convert the force of the wind into thrust that helps propel the ship.

Flettner Rotors were developed in the 1920s by German engineer Anton Flettner; the Flettner rotor ship Buckau set sail in 1925, crossing the North Sea and then the Atlantic.

Flettner rotors use a spinning cylinder to convert the force of the wind into thrust to help propel the ship by using the Magnus effect, a commonly observed effect in which a spinning ball, or cylinder in this case, curves away from its principal path.

The Magnus effect observes that a revolving body moving relatively to a surrounding fluid—in this case, air—is subjected not only to drag, but also to lift. As the speed of the cylinder—spinning at right angles to the flow—increases, the pressure decreases on the side of the cylinder where the natural flow and the spin-induce flow combine. The decrease in pressure generates lift, and the lift increases as the surface velocity increases (per Bernoulli’s theorem).

The Magnus effect can generate more lift per unit of projected area than typical airfoil forms; the drawback is that 10-20% of the output power is required to spin the cylinder.

Diagram of the Magnus effect applied to a ship, from Enercon. Click to enlarge.

Flettner sail rotors have been demonstrated on ships since the 1920s, with at least two vessels trialing the technology in recent years. The ETI project will be the first demonstration on such a large vessel and is intended to provide valuable insights into real world fuel savings and ease of operation.

The Expression of Interest (EoI) aims to identify organisations capable of providing Flettner rotor technology for a large internationally traded ship. The ETI intends to use the EoI submissions to select a preferred technology provider capable of moving to the shaping phase of a full scale demonstration project.

Respondents will need to set out how their technology will deliver fuel savings of at least 10% and also how they would design, supply, install, commission, test and then support Flettner rotor vessel installation. At sea testing of the performance of the Flettner rotor installation will take place for at least one year after installation.

This is a project to design, develop and fit Flettner rotor blades—effectively mechanical sails—which will then be demonstrated and tested at sea in real life conditions. Studies have shown that Flettner blades could be beneficial in certain sea conditions around the world reducing fuel consumption in ships of between 7 and 15%. However, there has been insufficient full scale demonstration on a suitable marine vessel to prove the technology benefits. Successfully demonstrating this would make the technology more attractive to shipping companies and investors. The technology, if proved successful, could also be retrofitted to existing shipping fleets and play a significant role in reducing the fuel costs, so improving environmental impact.

—Andrew Scott , manager for the ETI’s Flettner Rotor Supply, Install and Commission Project

The Expression of Interest for the Flettner Rotor Supply and Fit Project will close on 15 April 2016. The deadline for notification of intention to submit a proposal is 31 March 2016.

The ETI project is part of the marine element of its Heavy Duty Vehicles efficiency program.



I am not sure it will be a success:
a: Fuel cost is at very low levels.

b: They take up a lot of deck space so you can't stack containers or use them for a cruise ship (too much shadow (and noise?)

c: Maybe there will be a particular application for them, but I can't think of one at present.


This again? I guess nobody told them Germany's E-Ship 1 completed sea-trials in 2010 and has been carrying cargo for for 6 years. And a 10% improvement in fuel efficiency seems pretty lame when the Irish are aiming to build a fleet of 100% renewably powered hybrid sailing cargo ships;

10% ? That's what Skysail equipped ships are already getting - at lower costs;

Aaron Turpen

If these work as expected, they'd be perfect for tanker vessels hauling oil, compressed gasses, etc. as well as for many very large fishing vessels and the like. As mahonj points out, not so much for most cargo and passenger vessels.


Make them vertical wind turbines.


A 10% saving in fuel is huge when we talk about ships. This article claims one container ship is the equivalent of 50 million cars in pollutants...on one ship? My God! we are working on the wrong problem to clean up th air...we should be torpedoing ships:


Lad, maybe one container ship is the equivalent of 50 million cars in pollutants BUT one ship also carries a lot more freight. A lot more. When you factor in the amount of cargo that is moved shipping has the lowest emissions. Here are some numbers I dug up:

- Air cargo - 0.8063 kg of CO2 per Ton-Mile
- Truck - 0.1693 kg of CO2 per Ton-Mile
- Train - 0.1048 kg of CO2 per Ton-Mile
- Sea freight - 0.0403 kg of CO2 per Ton-Mile



I'm just looking at the amount of smog hese things produce...huge and most of it falls to the surface of the sea...not so much worried about GHG as the covering of the water.

If one reads the link, we are talking about the largest ICE in the World, it is 5 stories high, burns saudi bunker oil that's so thick you can walk on it and has no emissions controls. READ the LINK

Henry Gibson

What people don't realize is that sulphur in these fuels is an important nutrient for plant growth. A company in North Dakota was required (rightly so) to remove sulphur from its stack emissions, and it now sells the sulphur in bags, not only to neighboring farms but to all of US, The NOx that the engine generates is also plant food. The CO2 that the engines produce is clearly plant food. Crude oil was formed, at least partially, from plant and animal growth and retains many of the elements in the original plants. These engines could be operated most of the time in lean burn mode and already do at least some of the time and adjusted to produce the most NOx, not the least, and heat extracted from the exhaust with an organic rankine cycle to produce electricity with cooling from sea-water. Then the exhaust is fed directly into sea water to absorb sulfur oxides, nitrogen oxides Carbon dioxide, trace minerals and a small amount of hydrocarbons which can be eaten for energy by micro organisms. Much of this is already being done simply by the "smog" falling on the ocean surface, but this process could be vastly or half-vastly improved by very good mixing of exhaust and sea-water. Yes the sea-water is becoming less alkaline with the addition of CO2 but there is no way the Larger Seas will become actually acidic because of the massive concentration of calcium and magnesium ions in the water. Plants and animals reduce the CO2 in the sea by forming and holding carbohydrates and other organic materials and poison the earths atmosphere with more oxygen. Ships could also be required to inject into the water with their exhaust sufficient trace minerals to produce enough algae growth to absorb all of the CO2 released. and this would be one of the lowest cost methods available of CO2 reduction and indirectly collecting solar energy where solar cells are difficult to place.

Co-generation of heat-cooling and electricity, by many means including Micro-turbines is right now the fastest cheapest way to reduce CO2 release where natural gas is available except perhaps these ships where CO2 can be highly absorbed by the water. The Reagan library, recently much in the news, is heated cooled and lighted by co-generation.

The floating human created debris in the ocean can be collected and destroyed by ships with Wet air oxidation tanks. At 270 degrees Centigrade more or less, water will oxidize organic materials in it. CO2 could be directly absorbed by the ocean or collected as liquid. Energy from the heat produced could be use to move the collecting boat and inject the air into the oxidation tanks. Living or dead plants and animal can be sieved out of the water for emergency fuel. ..HG..


HG, sounds like you are talking about barge traffic, which runs at precisely the moderate rates to make your scheme attractive.

Flettner rotors could take advantage of the low profiles and long travel times of the barges. Similar rotors under the hull could reduce flow resistance, particularly in upstream movement.

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